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The photos on that page were taken with 8- and 14-inch telescopes. I expected a 6.5-meter one to have a more detailed image. Keck has a 10-meter aperture and i

by sp332 3y ago

The photos on that page were taken with 8- and 14-inch telescopes. I expected a 6.5-meter one to have a more detailed image. Keck has a 10-meter aperture and its image of Uranus looks like this: https://keckobservatory.org/keck_pictures_of_uranus_show_best_view_from_the_ground/ https://keckobservatory.org/keck_pictures_of_uranus_show_bes...

ceejayoz 3y ago
Webb is optimized for different things. https://news.berkeley.edu/2022/12/01/webb-space-telescope-keck-team-up-to-study-saturns-moon-titan https://news.berkeley.edu/2022/12/01/webb-space-telescope-ke... > Though the quality of the JWST and Keck images may look about the same to the untrained eye, de Pater noted that JWST has instruments that can measure aspects of Titan’s atmosphere that Keck cannot, complementing one another. In particular, JWST’s infrared spectroscopic capability allows it to pinpoint the altitudes of clouds and hazes with much better accuracy. > “By using spectrometers on JWST together with the optical image quality with Keck, we get a really complete picture of Titan,” she said, such as the heights of clouds, the atmosphere’s optical thickness, and the elevation of haze in the atmosphere. > In particular, at wavelengths where Earth’s atmosphere is opaque — that is, Titan cannot be seen from any Earth-based telescope — JWST can observe and provide information on the lower atmosphere and surface.
- divbzero 3y ago
  > the heights of clouds, the atmosphere’s optical thickness, and the elevation of haze in the atmosphere It amazes me that we can detect any of those with telescopes so far away. Does anyone have a rough explanation for how this is possible?
goodcanadian 3y ago
Bigger telescopes are mostly about capturing more photons to detect fainter objects. They don't really give you better resolution in most cases. Technically, a bigger telescope can give better resolution, but from the ground, the limit is usually atmospheric seeing. From orbit, it will be down to the quality of the optics, the resolution of the detector, and the precision of the tracking.
- dylan604 3y ago
  This is very much a basic misunderstanding with telescopes. Most people expect magnification. The amount of photons absorbed is something of a very esoteric concept to the uninitiated.
  - kridsdale1 3y ago
    Signal to noise ratio.
- BenjiWiebe 3y ago
  After ~150mm aperture, right? Highest magnification is approximately 2x the aperture in mm, and 300x is approximately the atmospheric limit.

by sp332 3y ago

ceejayoz 3y ago

Webb is optimized for different things. https://news.berkeley.edu/2022/12/01/webb-space-telescope-keck-team-up-to-study-saturns-moon-titan https://news.berkeley.edu/2022/12/01/webb-space-telescope-ke... > Though the quality of the JWST and Keck images may look about the same to the untrained eye, de Pater noted that JWST has instruments that can measure aspects of Titan’s atmosphere that Keck cannot, complementing one another. In particular, JWST’s infrared spectroscopic capability allows it to pinpoint the altitudes of clouds and hazes with much better accuracy. > “By using spectrometers on JWST together with the optical image quality with Keck, we get a really complete picture of Titan,” she said, such as the heights of clouds, the atmosphere’s optical thickness, and the elevation of haze in the atmosphere. > In particular, at wavelengths where Earth’s atmosphere is opaque — that is, Titan cannot be seen from any Earth-based telescope — JWST can observe and provide information on the lower atmosphere and surface.

divbzero 3y ago
> the heights of clouds, the atmosphere’s optical thickness, and the elevation of haze in the atmosphere It amazes me that we can detect any of those with telescopes so far away. Does anyone have a rough explanation for how this is possible?

goodcanadian 3y ago

Bigger telescopes are mostly about capturing more photons to detect fainter objects. They don't really give you better resolution in most cases. Technically, a bigger telescope can give better resolution, but from the ground, the limit is usually atmospheric seeing. From orbit, it will be down to the quality of the optics, the resolution of the detector, and the precision of the tracking.

dylan604 3y ago
This is very much a basic misunderstanding with telescopes. Most people expect magnification. The amount of photons absorbed is something of a very esoteric concept to the uninitiated.
- kridsdale1 3y ago
  Signal to noise ratio.
BenjiWiebe 3y ago
After ~150mm aperture, right? Highest magnification is approximately 2x the aperture in mm, and 300x is approximately the atmospheric limit.